Rights management (RM) and enforcement is highly desirable in connection with digital content such as digital audio, digital video, digital text, digital data, digital multimedia, etc., where such digital content is to be distributed to one or more users. Digital content could be static, such as a text document, for example, or it could be streamed, such as the streamed audio and video of a multimedia presentation. Typical modes of distribution of such content include tangible and intangible forms such as an optical disk, a cable-access feed, a feed from an electronic network such as the Internet, a feed from an over-the-air broadcast, etc. Upon being received by a user at an appropriate computing device thereof, such user renders the digital content with the aid of the computing device, appropriate rendering software, and appropriate output devices such as speakers, a video monitor, etc.
In one scenario, the content is distributed as a stream by a distributor as part of a pay-per-use service, such as for example an on-command digital television service, and the streamed content as distributed is protected by for example being encrypted. In another scenario, the content is distributed as a file by a distributor by any appropriate communications medium, such as for example a computer communications network, and the file of content as distributed is again protected by for example being encrypted. In either scenario, then, the user provides to a licensing service such as a licensor or the like a request including relevant data regarding the content and an appropriate form of payment. Upon accepting the payment, then, the licensor returns to the requesting user a content key (CK) by which the encrypted content may be decrypted by such user.
Typically, inasmuch as symmetric encryption and decryption is easier, faster, and less expensive than asymmetric encryption and decryption, the content key (CK) is symmetric. Also typically, the content key (CK) is returned by the licensor to the requesting user in a form so that such content key (CK) is available only to such user. For example, such content key (CK) can be provided to the user in an encrypted form and as part of a digital license or the like that specifies license rules that must be satisfied before such content is allowed to be decrypted and rendered by the user by way of an appropriate media system.
It is to be recognized that in some circumstances a user of such an RM system would prefer not to identify the content to be consumed thereby, both to the licensor and to those who may be able to access data maintained by the licensor. That is, such a user as a matter of privacy may wish to request the content key (CK) to render a particular piece of content without in fact identifying the content to the licensor returning such content key (CK). Reasons for avoiding such identification are many and varied and need not be set forth herein in any detail, although it is to be appreciated that such reasons could for example be grounded in avoiding embarrassment and/or humiliation that could result from such identification.
At any rate, it is to be appreciated that avoiding such identification of such content requires not only avoiding providing the name or any other identification of the content, but also avoiding providing any indicia that may lead to an identification of the content. For example, and most pertinent to the present disclosure, a user requesting from a licensor a particular content key (CK) corresponding to a particular piece of content could identify the content key (CK) only and not the corresponding content in an attempt to avoid identifying and being associated with such content. However, in identifying the content key (CK), it likely would not be difficult for the licensor to identify the corresponding content based on such identified content key (CK), and in doing so to associate the user with the content.
A need exists then, for a system and method to provide a user with some measure of privacy by allowing such user to request from a licensor a content key (CK) for a piece of content without identifying the content key (CK) or the content. In particular, a need exists for a method by which the requesting user sends to the licensor as part of a request an encrypted form of the content key (CK) in an obscured form that is unrecognizable to the licensor and yet that allows the licensor to decrypt the encrypted content key (CK) into a decrypted yet still obscured form that remains unrecognizable to the licensor. Thus, although the licensor decrypts same to result in the content key (CK), such decryption never results in the content key (CK) in a form identifiable to the licensor. As a result, the licensor cannot associate the content key (CK) and by extension the requesting user to a particular piece of content. Nevertheless, the licensor can note that the requesting user did in fact obtain a content key (CK) for some piece of content.